Now the db/service.php array can contain these extra keys to provide information
on how a webservice may be called:
'ajax' => true (Default is false)
Replaces the xx_is_allowed_from_ajax callback.
'loginrequired' => false (Default is true)
Means that this webservice can be called through lib/ajax/service-nosession.php
which sets NO_MOODLE_COOKIES to true (faster). This is only safe for webservices returning
static public data (e.g. get_string).
Juan Leyva